采用发光菌和统计法评估地下水水质 ——以“珠江三角洲”滨海小流域为例

以珠江三角洲滨海小流域地下水为研究对象,采用费氏弧菌(Vibrio ficheri)和化学指标主成分分析法综合评价不同人类活动背景下的地下水(8个饮用水井和6个观测井)以及海水水质.结果表明:15个水样中的阳离子以K+和Na+为主,占阳离子总量的平均百分比为71.55%±14.67%.阴离子的浓度差异较大,饮用水井(T1~T8)的阴离子以HCO3-为主,观测井(D1~D6)的阴离子以Cl-为主,平均百分比分别为53.84%±18.21%和66.37%±22.16%.除T3、T4和D3无毒外,其余水样对发光菌具有一定的抑制效应,其中D2和D4对发光菌的抑制率大于30%,为中毒性,海水水样则对发光菌产生了“刺激发光”效应,30min的发光抑制率为-12.45%;通过水样化学指标的主成分分析,计算井水的综合得分,排泄区D2~D4 (8~15m潜水含水层)得分较高,D5 (承压含水层)、D6 (基岩裂隙含水层)以及D1(5m潜水含水层)得分较低,唐家镇除T1地下水埋深最深(17.92m),得分最高,其余地下水(T2~T8)位于地表以下10m内的含水层,得分较低;发光抑制率与第一主成分具有良好的负相关性(P<0.05),经拟合方程预测的毒性结果准确率为75%,“假阴性”水样个数为0.

Application of luminescent bacteria and statistic method in groundwater quality assessment: A ease study in coastal catchments in the Pearl River Delta

Water samples from 8 domestic wells (Tangjia town), 6 observation wells (Zhuhai campus of SunYatsen University) and 1 from seawater as well in coastal catchments of Zhuhai City in the Pearl River Delta were selected as research objects. Water quality under natural and urbanized conditions was evaluated by using luminescent bacteria (Vibrio ficheri) and principal component analysis (PCA) of chemical parameters. The results showed that the primary cations of 15 samples were K+ and Na+, accounting for an averaged 71.55% of major cations. Major anions for domestic (T1~T8) and observation(D1~D6) wells were HCO3- (53.84%) and Cl- (66.37%), respectively. All samples except T3, T4 and D3 had inhibitory effect on luminescent bacteria, e.g. inhibitory ratio of D2 and D4 exceeded 30%, which can be considered as moderate toxic. Seawater stimulated luminescence and achieved a relative luminous inhibition of -12.45% within 30 min. General score of groundwater samples were calculated by extracting three principal components of PCA, yielding high scores at D2~D4 (unconfined aquifer) and low scores at D5 (confined aquifer), D6 (fissured aquifer) and D1 (unconfined aquifer) in the discharge area. In the comparative study catchment in Tangjia, the highest score was obtained from T1(17.92m below surface) and much low scores from the other domestic wells(T2~T8) with well depth less than 10m. A negative correlation (P<0.05) between relative luminous inhibition and the first component was identified, and 75% accuracy with zero “false negative” sample regarding toxicity prediction was obtained by fitting equation.